Michael Brougham

Multifunctional Ultracomposites: Piezoelectric Materials Grown On Binary Metallic Glasses

As MEMS devices enter the regime of the nanoscale, it becomes increasingly important to effectively scale each component. The present study explores the feasibility and advantages of a new class of "multifunctional ultracomposites" by examining the characteristics of a key piezoelectric, AlN, grown on a novel metastable alloy, Al-32 at.% Mo. Using a parameter optimization procedure and advanced tools such as XRD and TEM, we have demonstrated the following: the ultrasmooth surface of AlMo combined with its incredibly high nucleation site density together enable a competing growth pattern whereby the desired piezoelectric (0002) orientation dominates from the very outset of growth. Our initial results also suggest a third contributing factor and new physical phenomenon namely local epitaxial growth on nanocrystallites through the enhanced mechanical compliancy of the amorphous matrix. Taken together, this novel approach opens new possibilities in the NEMS-scale miniaturization of both actuation and detection capabilities with applications including self-sensing nanorobotics and scanning probe microscopy

Michael Brougham is doing his MSc in Materials Engineering under the supervision of Dr. David Mitlin and Dr Fraser Forbes.